Concentrating solar power (CSP) is an effective way to convert solar energy into electricity with an economic energy-storage capability for grid-scale, dispatchable renewable power generation. CSP plants need to reduce costs to be competitive with other power generation methods. Two ways to reduce CSP cost are to increase solar-to-electric efficiency by supporting a high-efficiency power conversion system, and to use low-cost materials in the system. The state-of-the-art molten-salt systems have limited potential for cost reduction and improving power-conversion efficiency with high operating temperatures. Even with significant improvements in operating performance, these systems face challenges in satisfying the cost and performance targets.
Unlike a conventional molten-salt based CSP plant, this design uses gas/solid, two-phase flow as the heat-transfer fluid (HTF); separated solid particles as the storage media; and stable, inexpensive materials for the high-temperature energy storage containment. A key enabling technology for the solid-particle based CSP system is a high-temperature, high-efficient particle receiver. Achieving high temperatures and desired particle flow-rate is a challenge with current systems under development using open- or rotating-cavity designs. Open-cavity receivers have several potential concerns affecting the receiver performance: (1) particle trajectories are affected by wind, (2) falling particles can entrain cold air through the cavity opening, (3) solar flux passes through the particle stream and heats up the receiver's back wall, and (4) the freely falling particles may not have adequate residence time in the heating region. Thus, there remains a need for improved CSP systems and solar receivers.